Alaska's drinking age was 19 when I came to Alaska in 1971. By the time Air Force personnel were able to get and assignment to Alaska they were at least 19, usually older. I was 21 in March and arrived in Alaska in May of the same year. Alaska was an Over Seas assignment and one had to have a 5 level before coming here. That usually took two years. So it was not a problem since everyone was of drinking age when they arrived.
I went into the Air Force at the age of 18. Got to California and could not drink off base, but was able to sit down and have a beer after work at the AAFES Snack Bar. Was also able to go to the Airman's club and have a drink of anything I wanted. State Law was not enforced on base. Yes I did get blitzed a few times, but my older friends took care of me. That's the way it was back then in the military. I've turned many a young, passed out, drunk, over onto his face, so he would not drown when he threw-up. Part of dorm (AF for Barracks) life.
I became an NCO at the tender age of 20. Still could not drink off base, yet I could lead a squad of men in battle. I felt discriminated against by the State Of California.
I have always said if a man is old enough to carry a gun, he or she is old enough to drink.